Insole

ABSTRACT

A removable full length insole for insertion into open style footwear, includes a forefoot portion, a heel portion and a mid-foot portion connecting together the forefoot portion and the heel portion; a uniform thickness cushioning layer of a resilient material extending through the forefoot portion, heel portion and mid-foot portion; a substantially dome shaped pillow extending down from the cushioning layer at the forefoot portion and heel portion; and an arrangement for maintaining the insole in position in the footwear during a gait.

BACKGROUND OF THE INVENTION

The present invention relates generally to shoe insoles or inserts, andmore particularly, to insoles particularly adapted to be used with openstyle footwear.

Various types of insoles are known which fit within shoes in order tocorrect various foot problems, alleviate pain and otherwise provide morecomfort to the wearer. Examples of such insoles are those sold by theassignee of the present invention under the trademark Dr. SCHOLL'S®.

However, when wearing open style footwear where the perimeter of thefootwear is exposed, such as sandals, clogs, slides, slingbacks and thelike, the boundary of the footwear is not sufficient to hold the insolein position during a normal gait. As a result, such insoles cannot beused with open style footwear.

Further, with conventional shoes, the wearer's foot is restricted by theupper which is connected to the outer and/or inner sole. As a result,any insole placed therein is also limited by the same upper. This meansthat the edges of the insole can be relatively thick, since the wearerwill not notice such thickness at the edges. However, this is not truewith open style footwear in which the wearer's foot is given greaterfreedom of movement. As a result, the wearer may notice a step betweenthe relatively thick edge of the insole and the inner sole of thefootwear, causing discomfort to the wearer.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide aninsole that overcomes the problems with the aforementioned prior art.

It is another object of the present invention to provide an insole thatcan be worn with open style footwear.

It is still another object of the present invention to provide an insolethat remains in place in the open style footwear during use.

It is yet another object of the present invention to provide an insolethat provides cushioning at the forefoot and heel areas.

It is a further object of the present invention to provide an insolethat tapers in thickness toward the peripheral edges thereof.

It is a yet further object of the present invention to provide an insolethat is easy and economical to make and use.

In accordance with an aspect of the present invention, an insole forinsertion into footwear, includes at least one of a forefoot portion anda heel portion; at least one of the forefoot portion and heel portionbeing formed by a cushioning layer of a resilient material whichprovides a cushioning function, and a substantially dome shaped pillowextending down from the cushioning layer; and an arrangement formaintaining the insole in position in the footwear during a gait.

Preferably, the insole is a full length insole formed from the forefootportion, the heel portion and a mid-foot portion connecting together theforefoot portion and the heel portion. More preferably, the cushioninglayer extends through the forefoot portion, heel portion and mid-footportion, and each of the forefoot portion and heel portion includes asubstantially dome shaped pillow extending down from the cushioninglayer thereat.

The cushioning layer and the pillow are formed from the same material asa unitary, one-piece structure.

In one embodiment, the cushioning layer and pillow are formed from afoam material. In such case, the arrangement for maintaining the insolein position can include either an adhesive at a lower surface of theinsole, or for example, a non-permanent adhesive that permits removal ofthe insole from the footwear and repositioning the insole in thefootwear, or alternatively, a high friction lower surface of the insole.

In another embodiment, the cushioning layer and pillow are formed from aviscoelastic gel material. In such case, the arrangement for maintainingthe insole in position includes either a non-permanent adhesive at thelower surface, or a tackifier added to the gel material. Preferably, thegel material under the dome shaped pillow is formed by a plurality ofspaced apart spring walls formed from the viscoelastic gel, the springwalls extending from a lower surface of the cushioning layer. The springwalls each have a height which is greatest at a center of the pillow andwhich tapers in height toward edges of the pillow. Preferably, each ofthe spring walls is formed in a generally sinusoidal wave shape.

Preferably, the cushioning layer has a substantially uniform thicknessof about 2 mm and the pillow has a height less than about 3 mm above theuniform layer, and the cushioning layer tapers in thickness toward aperiphery of the insole.

A top cover can also be secured to an upper surface of the cushioninglayer.

The above and other features of the invention will become readilyapparent from the following detailed description thereof which is to beread in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a left insole according to a firstembodiment of the present invention;

FIG. 2 is a top plan view of the left insole;

FIG. 3 is a bottom plan view of the left insole according to oneembodiment;

FIG. 4 is a front elevational view of the left insole FIG. 4;

FIG. 5 is a right side elevational view of the left insole;

FIG. 6 is a cross-sectional view of the left insole, taken along line6-6 of FIG. 2;

FIG. 7 is a bottom plan view of a left insole according to a secondembodiment of the present invention;

FIG. 8 is a cross-sectional view of the left insole of FIG. 7, takenalong line 8-8 thereof; and

FIG. 9 is a perspective view of a portion of the left insole of FIG. 7.

DETAILED DESCRIPTION

Referring to the drawings in detail, and initially to FIGS. 1-6 thereof,a left insole 10 according to a first embodiment of the presentinvention is adapted to be placed in an article of footwear, as is wellknown. A right insole (not shown) is identical to left insole 10 and isa mirror image thereof.

Insole 10 was designed to fit the shape of a human left foot andtherefore includes a curved toe or forefoot portion 12, a heel portion14, and a mid-foot portion 16 which connects forefoot portion 12 andheel portion 14 together.

Insole 10 is formed by a generally planar cushioning layer 18, having agenerally dome shaped, lower pillow 20 extending from the lower surfaceof cushioning layer 18 at forefoot portion 12 and a generally domeshaped, lower pillow 22 extending from the lower surface of cushioninglayer 18 at heel portion 14.

In one embodiment, layer 18 and pillows 20 and 22 are formed as aunitary, one-piece layer of the same material, which is preferably apolyurethane foam. Specifically, in the first embodiment, insole 10formed by cushioning layer 18 and pillows 20 and 22 is made from aresilient foam material that provides a conventional cushioningfunction. In effect, cushioning layer 18 and pillows 20 and 22 are atypical foam mechanical spring, shock absorption layer that cushions thefoot, in order to decrease pressure.

Cushioning layer 18 and pillows 20 and 22 can be made from any suitablematerial including, but not limited to, any flexible material which cancushion and absorb the shock from heel strike on the insole. Suitableshock absorbing materials can include any suitable foam, such as but notlimited to, cross-linked polyethylene, poly(ethylene-vinyl acetate),polyvinyl chloride, synthetic and natural latex rubbers, neoprene, blockpolymer elastomer of the acrylonitrile-butadiene-styrene orstyrene-butadienestyrene type, thermoplastic elastomers,ethylenepropylene rubbers, silicone elastomers, polystyrene, polyurea orpolyurethane; most preferably a polyurethane foam made from flexiblepolyol chain and an isocyanate such as a monomeric or prepolymerizeddiisocyanate based on 4,4′-diphenylmethane diisocyanate (MDI) or toluenediisocyanate (TDI). Such foams can be blown with freon, water, methylenechloride or other gas producing agents, as well as by mechanicallyfrothing to prepare the shock absorbing resilient layer. Such foamsadvantageously can be molded into the desired shape or geometry.Non-foam elastomers such as the class of materials known as viscoelasticpolymers, or silicone gels, which show high levels of damping whentested by dynamic mechanical analysis performed in the range of −50degrees C. to 100 degrees C. may also be advantageously employed. Aresilient polyurethane can be prepared from diisocyanate prepolymer,polyol, catalyst and stabilizers which provide a waterblown polyurethanefoam of the desired physical attributes. Suitable diisocyanateprepolymer and polyol components include polymeric MDI M-10 (CAS9016-87-9) and Polymeric MDI MM-103 (CAS 25686-28-6), both availablefrom BASF, Parsippany, N.J.; Pluracol 945 (CAS 9082-00-2) and Pluracol1003, both available from BASF, Parsippany, N.J.; Multrinol 9200,available from Mobay, Pittsburgh, Pa.; MDI diisocyanate prepolymer XAS10971.02 and polyol blend XUS 18021.00 available from the Dow ChemicalCompany, Midland, Mich.; and Niax 34-28, available from Union Carbide,Danbury, Conn. These urethane systems generally contain a surfactant, ablowing agent, and an ultra-violet stabilizer and/or catalyst package.Suitable catalysts include Dabco 33-LV (CAS 280-57-9,2526-71-8), DabcoX543 (CAS Trade Secret), Dabco T-12 (CAS 77-58-7), and Dabco TAC (CAS107-21-1) all obtainable from Air Products Inc., Allentown, Pa.; FomrezUL-38, a stannous octoate, from the Witco Chemical Co., New York, N.Y.or A-1 (CAS 3033-62-3) available from OSI Corp., Norcross, Ga. Suitablestabilizers include Tinuvin 765 (CAS 41556-26-7), Tinuvin 328 (CAS25973-55-1), Tinuvin 213 (CAS 104810-48-2), Irganox 1010 (CAS6683-19-8), Irganox 245 (CAS 36443-68-2), all available from the CibaGeigy Corporation, Greensboro, N.C., or Givsorb UV-1 (CAS 057834-33-0)and Givsorb UV-2 (CAS 065816-20-8) from Givaudan Corporation, Clifton,N.J. Suitable surfactants include DC-5169 (a mixture), DC190(CAS68037-64-9), DC197 (CAS69430-39-3), DC-5125 (CAS 68037-62-7) allavailable from Air Products Corp., Allentown Pa. and L-5302 (CAS tradesecret) from Union Carbide, Danbury Conn. Alternatively, lower layer 18can be a laminate construction, that is, a multilayered composite of anyof the above materials. Multilayered composites are made from one ormore of the above materials such as a combination of polyethylene vinylacetate and polyethylene (two layers), a combination of polyurethane andpolyvinyl chloride (two layers) or a combination of ethylene propylenerubber, polyurethane foam and ethylene vinyl acetate (3 layers).

Preferably, cushioning layer 18 and pillows 20 and 22 are made from aurethane molded material, and more preferably, a polyurethane elastomermaterial.

The materials of cushioning layer 18 and pillows 20 and 22 can beprepared by conventional methods such as heat sealing, ultrasonicsealing, radio-frequency sealing, lamination, thermoforming, reactioninjection molding, and compression molding and, if necessary, followedby secondary die-cutting or in-mold die cutting. Representative methodsare taught, for example, in U.S. Pat. Nos. 3,489,594; 3,530,4894,257,176; 4,185,402; 4,586,273, in the Handbook of Plastics, Herber R.Simonds and Carleton Ellis, 1943, New York, N.Y., Reaction InjectionMolding Machinery and Processes, F. Melvin Sweeney, 1987, New York,N.Y., and Flexible Polyurethane Foams, George Woods, 1982, New Jersey,whose preparative teachings are incorporated herein by reference. Forexample, the innersole can be prepared by a foam reaction moldingprocess such as taught in U.S. Pat. No. 4,694,589.

Pillows 20 and 22 extend downwardly below the lower surface 18 a ofcushioning layer 18 to provide extra cushioning at the ball of the footarea of forefoot portion 12 and at heel portion 14. Preferably,cushioning layer 18 has a constant thickness throughout, althoughcushioning layer 18 preferably tapers in thickness toward the peripheraledge 18 b of insole 10 in order to prevent a user from feeling an edgedrop-off. For example, cushioning layer 18 can have a thickness of about2 mm which tapers down to a thickness of about 1 mm at the peripheraledge 18 b of insole 10, and with the combined thickness of cushioninglayer and either pillow 20 or 22 having a thickness of about 5 mm.

A top cover layer 24 can be secured to the upper surface of cushioninglayer 18, although such a top cover layer 24 is not required. In suchcase, top cover layer 24 can be made from any suitable materialincluding, but not limited to, fabrics, leather, leatherboard, expandedvinyl foam, flocked vinyl film, coagulated polyurethane, latex foam onscrim, supported polyurethane foam, laminated polyurethane film orin-mold coatings such as polyurethanes, styrene-butadiene-rubber,acrylonitrile-butadiene, acrylonitrile terpolymers and copolymers,vinyls, or other acrylics, as integral top covers. Desirablecharacteristics of top cover layer 24 include good durability, stabilityand visual appearance. It is also desirable that top cover layer 24 havegood flexibility, as indicated by a low modulus, in order to be easilymoldable. The bonding surface of top cover layer 24 should provide anappropriate texture in order to achieve a suitable mechanical bond tothe upper surface of cushioning layer 18. Preferably, the material oftop cover layer 24 is a fabric, such as a brushed knit laminate topcloth (brushed knit fabric/urethane film/non-woven scrim cloth laminate)or a urethane knit laminate top cloth. Preferably, top cover layer 24 ismade from a polyester fabric material, and preferably has a thickness ofabout 0.02 inch.

It will be appreciated that insole 10 is preferably a full lengthinsole, that is, extends along the entire foot. Typically, insole 10would be sized corresponding to shoe sizes and would be provided insized pairs. Alternatively, insole 10 may be trimmed to the requirementsof the user. In this regard, arcuate pattern trim lines (not shown) maybe formed on the lower surface of forefoot portion 12 of insole 10,which are representative of various sizes of the human foot. The patterntrim lines may be imprinted by conventional printing techniques,silkscreening and the like. As an alternative, the pattern trim linesmay be formed as shallow grooves, or be perforated, so that a smallersize insole may be separated by tearing along the appropriate trimlines, which tearing operation is facilitated by the inclusion ofperforations. Thus, forefoot portion 12 can be trimmed so that forefootportion 12 fits within the toe portion of open style footwear.

Alternatively, a pattern trim line can be provided on the lower surfaceof cushioning layer 18 to cut around the thong of some types of openstyle footwear, if necessary.

Alternatively, insole 10 may be a ¾ length insole designed to fit arange of shoe sizes without the need of trimming. In this regards,insole 10 extends along the approximately ¾ of the foot, from the heelto the ball of the foot.

In order to secure insole 10 to the open style footwear, an area ofadhesive 26, for example, by a double sided adhesive tape, is formedalong the length of the lower surface of cushioning layer 18, and iscovered by a release sheet 28. In this manner, a user merely removesrelease sheet 28 and adheres insole 10 to the footwear. Adhesive 26 canbe a permanent adhesive or a release adhesive that permits removal andreapplying or repositioning of insole 10 in the footwear.

Alternatively, lower surface 18 a of cushioning layer 18 can be providedas a high friction surface to maintain insole 10 in position in thefootwear. For example, synthetic rubber adhesive coating (not shown) canbe added to lower surface 18 a of cushioning layer 18 for this purpose.

Accordingly, with insole 10, cushioning pillows 20 and 22 are providedat the ball of the foot area of forefoot portion 12 and at heel portion14 where most of the impact and forces occur during a gait. Further,such insole 10 fits within open style footwear, and will remain inposition in such open style footwear during wearing by the user. At thesame time, however, the wearer, because of the taper at the peripheraledge thereof, does not feel any edge drop-off, thereby enhancing comfortto the wearer.

Referring now to FIGS. 7-9, a left insole 110 according to a secondembodiment of the present invention will now be described. A rightinsole (not shown) is identical to left insole 110 and is a mirror imagethereof.

Insole 110 has the same shape as insole 10 of FIGS. 1-6, and thereforeincludes a curved toe or forefoot portion 112, a heel portion 114, and amid-foot portion 116 which connects forefoot portion 112 and heelportion 114 together.

Insole 110 is formed by a generally planar cushioning layer 118, havinga generally dome shaped, lower pillow 120 extending from the lowersurface of cushioning layer 118 at forefoot portion 112 and a generallydome shaped, lower pillow 122 extending from the lower surface ofcushioning layer 118 at heel portion 114.

In this embodiment, layer 118 and pillows 120 and 122 are formed as aunitary, one-piece layer of a gel material. The gel material can be ofthe same general type described in U.S. Pat. No. 6,598,321 to the sameassignee herein, and the entire disclosure of which is incorporatedherein by reference.

Thus, gel layer 118 and pillows 120 and 122 can be made from a non-foamelastomer such as the class of materials known as viscoelastic polymersor silicone gels, which show high levels of damping when tested bydynamic mechanical analysis performed in the range of −50 degree Celsiusto 100 degrees Celsius. Because the mechanical properties of the gel aremore viscous than elastic, the gel provides a high energy absorption.Gels that can be used according to the present invention arethermoplastic elastomers (elastomeric materials), such as materials madefrom many polymeric families, including but not limited to the Kratonfamily of styrene-olefin-rubber block copolymers, thermoplasticpolyurethanes, thermoset polyurethanes, thermoplastic poly olefins,polyamides, polyureas, polyesters and other polymer materials thatreversibly soften as a function of temperature. The preferred elastomersare a Kraton block copolymer of styrene/ethylene-co-butylene/styrene orstyrene/butadiene/styrene with mineral oil incorporated into the matrixas a plasticizer, or polyurethane gels.

Insole 110 can be secured to the open style footwear by using the tackproperties of the gel. In this regard, it is preferred that the tack ofthe gel is enhanced by incorporating a tackifier into the gelcomposition to increase the friction/tack of the gel surface. Suitabletackifiers include a petroleum hydrocarbon resin sold under thedesignation I-Mark V by Idemitsu Kosan Co., Ltd. of Tokyo, Japan; therosin sold under the trademark ASYLVALITE® under designation RE 80 forSEBS gels; and phenolsulfonic acid ester sold under the trademarkAMESAMOLL® for a polyurethane (PU) gel. The desired tack is preferablybetween 120 and 250 grams, as determined by a probe tack tester soldunder the trademark APOLYKEN®, at one second contact time.

Preferably, dome shaped pillows 120 and 122 are formed by thin andspaced apart elastic and resilient spring walls 130 and 132 which areformed integrally as one piece with cushioning layer 118 in a repeatingorder, extending down from the lower surface of layer 118 at forefootportion 112 and heel portion 114.

Thin spring walls 130 extend substantially in the lengthwise directionof insole 110 from the forward end to the rearward end of pillow 120.The height of spring walls 130 extends down such that spring walls 130located toward the center of pillow 120 have a greater height thanspring walls 130 located toward the edges of pillow 120, with springwalls 130 therebetween tapering down, as shown best in FIG. 7. In thismanner, the lower ends of spring walls 130 in pillow 120 form asubstantially dome shape. The overall thicknesses or heights ofcushioning layer 118 and pillows 120 and 122 are similar to those ofcushioning layer 18 and pillows 20 and 22, as described above. As aresult, the height of spring walls 130 at the center of each pillow canreach a height of about 2-3 mm above the uniform layer, and the constantor uniform thickness or height of cushioning layer 118 can be about 2mm.

In like manner, thin elastic and resilient spring walls 132 are formedin a V-shaped pattern in pillow 122 at heel portion 114. Spring walls132 are formed with the same varying height as spring walls 130. Thus,the heights of spring walls 132 extend down such that spring walls 132located toward the center of pillow 122 have a greater height thanspring walls 132 located toward the edges of pillow 122, with springwalls 132 therebetween tapering down. In this manner, the lower ends ofspring walls 132 in pillow 122 form a substantially dome shape. Theoverall thicknesses or heights of cushioning layer 118 and pillows 120and 122 are similar to those of cushioning layer 18 and pillows 20 and22, as described above. As a result, the heights of spring walls 132 atthe center of each pillow can reach a height of about 2-3 mm, and theconstant or uniform thickness or height of cushioning layer 118 can beabout 2 mm.

In the embodiment of FIGS. 7-9, thin, spaced apart spring walls 130 and132 are formed as parallel, spaced apart, sinusoidal shaped wavepatterns. However, the present invention is not so limited, and can beformed as any of the embodiments described in U.S. Pat. No. 6,598,321.Further, the spacing between thin spring walls 130, 132, the number ofspring walls 130, 132, the pitch of the sinusoidal wave patterns in thespring walls 130, 132, etc. may also be varied.

As with cushioning layer 18, cushioning layer 118 preferably tapers inthickness toward the peripheral edge 118 b of insole 110 in order toprevent a user from feeling an edge drop-off. For example, cushioninglayer 118 can have a uniform thickness of 2 mm which tapers down to athickness of about 1 mm at the peripheral edge 118 b of insole 110.

A top cover layer (not shown), which is the same as top cover layer 24,can be secured to the upper surface of cushioning layer 118, althoughsuch a top cover layer is not required.

Although the present invention uses the term insole, it will beappreciated that the use of other equivalent or similar terms such asinnersole or insert are considered to be synonymous and interchangeable,and thereby covered by the present claimed invention.

The present invention is also applicable to insoles other than fulllength insoles, such as heel cushions and ball of foot cushions.

Further, although the present invention has been discussed in relationto a removable insole, it can be incorporated as a permanent inner solein footwear, such as a shoe or the like.

Having described specific preferred embodiments of the invention withreference to the accompanying drawings, it will be appreciated that thepresent invention is not limited to those precise embodiments and thatvarious changes and modifications can be effected therein by one ofordinary skill in the art without departing from the scope or spirit ofthe invention as defined by the appended claims.

1. An insole for insertion into footwear, comprising: a) at least oneof: i) a forefoot portion, and ii) a heel portion; b) at least one ofsaid forefoot portion and heel portion being formed by: i) a cushioninglayer of a resilient material which provides a cushioning function, andii) a substantially dome shaped pillow extending down from saidcushioning layer; and c) an arrangement for maintaining said insole inposition in said footwear during a gait.
 2. An insole according to claim1, wherein said insole is a full or ¾ length insole formed from saidforefoot portion, said heel portion and a mid-foot portion connectingtogether said forefoot portion and said heel portion.
 3. An insoleaccording to claim 2, wherein said cushioning layer extends through saidforefoot portion, heel portion and mid-foot portion, and each of saidforefoot portion and heel portion includes a said substantially domeshaped pillow extending down from said cushioning layer thereat.
 4. Aninsole according to claim 1, wherein said cushioning layer and saidpillow are formed from the same material as a unitary, one-piecestructure.
 5. An insole according to claim 1, wherein said cushioninglayer and pillow are formed from a foam material.
 6. An insole accordingto claim 5, wherein said arrangement for maintaining said insole inposition includes an adhesive at a lower surface of the insole.
 7. Aninsole according to claim 6, wherein said adhesive is a release adhesivethat permits removal of the insole from the footwear and repositioningthe insole in the footwear.
 8. An insole according to claim 5, whereinsaid arrangement for 10 maintaining said insole in position includes ahigh friction lower surface of the insole.
 9. An insole according toclaim 1, wherein said cushioning layer and pillow are formed from aviscoelastic gel material.
 10. An insole according to claim 9, whereinsaid arrangement for maintaining said insole in position includes atackifier added to said gel material.
 11. An insole according to claim9, wherein said gel material is formed by a plurality of spaced apartspring walls formed from said viscoelastic gel, said spring wallsextending from a lower surface of said cushioning layer.
 12. An insoleaccording to claim 11, wherein said spring walls each have a heightwhich is greatest at a center of said pillow and which tapers in heighttoward edges of said pillow.
 13. An insole according to claim 11,wherein each of said spring walls is formed in a generally sinusoidalwave shape.
 14. An insole according to claim 1, wherein said cushioninglayer has a substantially uniform thickness of about 2 mm and saidpillow has a height less than about 3 mm.
 15. An insole according toclaim 1, wherein said cushioning layer tapers in thickness toward aperiphery of said insole.
 16. An insole according to claim 1, furthercomprising a top cover secured to an upper surface of said cushioninglayer.